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Updated: Apr 14, 2026

Study of the DNA Damage Checkpoint using Xenopus Egg Extracts
Published on: November 5, 2012
Phosphorylation of Xenopus p31(comet) potentiates mitotic checkpoint exit
Min Mo1, Alexei Arnaoutov1, Mary Dasso1
1a Laboratory of Gene Regulation and Development; National Institute of Child Health and Human Development; National institutes of Health ; Bethesda , MD USA.
Abstract:
p31(comet) plays an important role in spindle assembly checkpoint (SAC) silencing. However, how p31(comet)'s activity is regulated remains unclear. Here we show that the timing of M-phase exit in Xenopus egg extracts (XEEs) depends upon SAC activity, even under conditions that are permissive for spindle assembly. p31(comet) antagonizes the SAC, promoting XEE progression into anaphase after spindles are fully formed. We further show that mitotic p31(comet) phosphorylation by Inhibitor of nuclear factor κ-B kinase-β (IKK-β) enhances this role in SAC silencing. Together, our findings implicate IKK-β in the control of anaphase timing in XEE through p31(comet) activation and SAC downregulation.
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